Looking away, Vaughn found Jane's knowing eye on him. It was a distinctly irritating sensation. He was the one who was supposed to be doling out the sardonic looks, not the other way around. It was an unacceptable inversion of the established world order.

"After you, Miss Wooliston," he drawled in tones of exaggerate ennui.

Jane cast him a shrewd look, but said nothing. Instead, she took up a candle from the collection on the table in the hall and led the way down the right hand corridor. Her silence was more damning than any knowing comment.

Jane led him to a small parlor, lined with books and furnished sparsely with furniture as heavy and dark as the weather outside the window.

"Well?" Jane inquired, with an arch of one light brow.

It was, Vaughn had to admit, an effective trick. By never identifying the question, one got all sorts of interesting answers.

Dropping into a red-cushioned chair, he rested his palms comfortably over the arms. "Miss Alsworthy and I have a further appointment with your friend. We meet in Hyde Park, the day after tomorrow."

"His Majesty's review of the first division of the London volunteers."

"None other." Vaughn watched the drops of rain splatter against the windowpanes. "Are we meant to be party to an assassination?"

"I don't know." The words cost her an obvious effort. Jane's well-shaped lips pressed tightly together. "He managed to evade us at Vauxhall."

"He?"

"I use the masculine pronoun for the sake of convenience. Nothing more."

Vaughn crossed his legs at the ankle, admiring the sparkle of his silver and diamond buckles. "I trust you investigated Rathbone?"

"Naturally." Jane circled the room, her muslin skirts whispering softly against her legs. "He possessed the usual revolutionary paraphernalia. Tattered tracts, treasonous correspondence with like-minded colleagues, a half-written treatise on political philosophy — none of it the least bit of use."

"No telltale manuscript by the bed? No sampler over the hearth embroidered with charming pictures of black tulips?"

"Rathbone isn't the embroidering kind," returned Jane. "His laboratory, however…" She paused, as though calculating how far to confide in him. "I believe you have some experience with natural philosophy, my lord."

Vaughn shook his head in demurral. "Only that of an amateur, a dabbler, a dilettante."

"That," commented Jane severely, "is far too many words to describe a nullity."

Vaughn accepted the rebuke with a casual inclination of his head.

"We found something curious in Rathbone's chambers," said Jane, watching Vaughn closely.

"Natural philosophers are curious sorts," provided Vaughn.

"We found vials of liquid mercury, several bowls of red crystals, lenses" — Jane ticked the items off on her fingers — "and a large canister, carefully stoppered, which, when we opened it, appeared to contain nothing at all. Yet someone went to the trouble of keeping it hermetically sealed with several layers of wax."

"An empty container?" Memory shifted and fell into place, an explanation far from simple but laughably prosaic. "Rathbone's experiments are beyond my humble powers, but I might be able to shed some little light on the discovery."

"Please do," invited Jane.

Vaughn ignored the light vein of sarcasm. "Have you ever heard of Priestley's treatise on air?" Without waiting for Jane's answer, he went on, "Apparently, like the rest of us, air is a deceiver. Rather than one element, it is several."

"Rather like the petals of the Tulip," mused Jane.

Vaughn acknowledged the point with a nod. "According to Priestley, by applying the right sorts of heat or chemicals, one could isolate the elements within the element, creating different sorts of gasses from the original air, all invisible to the naked eye. I can't imagine why one would want to," Vaughn added as an afterthought, "but there you have it."

"And Rathbone," concluded Jane, "was a student of Priestley."

"Precisely." Vaughn stretched out his legs before the fire. "Your empty container in fact was filled with a distilled element of some sort, which you unknowingly released back into the air whence it came. Tsk, tsk, Miss Wooliston. Weeks of scientific endeavor lost in the curiosity of a moment. Pandora's legacy lives on."

Jane frowned at him. "But what of the red powder? Miss Gwen believes it to be a new incendiary of some sort."

"A distillation of mercury, turned to crystal." Vaughn dabbed at his mouth with a lace-edged handkerchief. "I am unfamiliar with the process, but I believe it is one of the chemicals Priestley used in his experiments."

Jane looked like a cat who had licked at a bowl of cream to find it gone sour. "There were scorch marks on several of the tables, and yet not of the sort left by a candle."

"Your lenses," explained Vaughn. "One heats the chemicals with a so-called burning lens, by refracting sunlight through the lens to create heat and even flame."

Jane rested both hands on the windowsill. "In other words," she said, to the raindrops slipping down the glass, "there is a perfectly innocent explanation for all of it."

"I fear so," said Vaughn pleasantly. "As much as I regret to disappoint a lady."

"What a pity," said Jane wryly. "I had hoped it was an infernal machine in the making, rather than merely…empty air."

"I believe Priestley called it de-phlogisticated air," put in Vaughn helpfully.

Ignoring him, Jane took a slow turn about the room, coming to rest with one hand on the head of a bust of Aristotle. Her index finger tapped lightly against the great philosopher's carved cranium.

"Just because his scientific interests are legitimate doesn't mean that Rathbone isn't our man," said Jane, thinking aloud. "Even mad fanatics have hobbies."

"Stamp collecting, for example," put in Vaughn. "Collecting novelty porcelain."

Jane frowned at him. "Bedeviling one's friends and associates."

"I consider that less a hobby and more an avocation." Vaughn smiled serenely at Jane. "Every man needs something to give his life purpose."

"For now, I fear your purpose will have to be dogging Miss Alworthy's heels to His Majesty's review of the troops. I trust you shan't find it too onerous a task."

The gods planned their torments well: Sisyphus, doomed to roll the same rock eternally uphill; Tantalus, tempted with water, yet never allowed to drink; and he, poised as de facto bodyguard to the one women he wanted, but could never have.

It would, thought Vaughn grimly, be so much easier were she a member of the demimonde. Then he could simply make her his mistress, without regard to recurrent wives or the slings and arrows of the sharp-tongued harridans of the ton.

"I assume you will be there as well?"

"No," said Jane shortly. "I leave London in the morning. There are matters abroad that demand immediate attention."

Raising his quizzing glass to one eye, Vaughn regarded Jane in a silent demand for further information.

Jane regarded him right back. Her expression seemed to imply that she had no problem staring people out of countenance without artificial aids, and if he thought she was going to answer, he was quite mad.

"You're leaving us to the Black Tulip's tender mercies?" Vaughn drawled.

"Or the Black Tulip to yours," replied Jane blandly.

"In other words," suggested Vaughn, watching Jane closely, "you want me to keep the Black Tulip busy while you go about your business elsewhere."

Watching Jane's lips curve in a Sphinx-like smile, it occurred to Vaughn that Jane's assignment might have as much to do with keeping him busy as the Black Tulip. Their alliance, such as it was, was an uneasy one at best, and he knew Jane's associates continued to regard him with outright suspicion. The notion amused him. But he knew it would be useless to try to get Jane to say anything more on the topic.

Accepting defeat, Vaughn lowered his glass and leaned back in his chair. It was clearly well used, the cushions molded themselves obligingly to his body. "What do you believe the Black Tulip intends?" he asked.

"One." Jane held up a finger in illustration. "The Black Tulip does exactly what he claimed. He uses this opportunity to pass further instructions along to Miss Alsworthy."

"Unlikely," interrupted Vaughn lazily. "If the Tulip wanted a tкteа-tкte, he wouldn't have tolerated the presence of an escort."

"He might, of course, stage a diversion to separate you from Miss Alsworthy. Or he might use more subtle means to communicate with her, such as a note tucked into her reticule, in which case your presence is immaterial."

"But you don't believe that is the case."

"No," said Jane heavily.

"Option two," provided Vaughn, holding up two fingers on her behalf. "The review is merely a diversion. The Tulip lures us to Hyde Park while he conducts his dastardly business elsewhere."

"By far the likeliest scenario," conceded Jane. "However, that's really option three. You missed one."

Vaughn raised a quizzical brow.

"An attempt of some kind on the royal family," prompted Jane, as though to a slow student. "Why your presence would be imperative for that, however, I can't think. Nor can I imagine how Miss Alsworthy would be of any use, unless the Tulip intended to use her to distract the guards protecting Their Majesties."

"But you find that improbable."

"Only a fool would attempt an assassination or a kidnapping in so public a place. The Black Tulip has proved that he is anything but a fool. On the other hand," she added thoughtfully, "killing off his operatives in Ireland was not a well-reasoned act."